CAE

Fluxiss Ran 12 Brutal Load Cases on a Composite Pressure Vessel And Found Exactly What Was Wrong Before It Flew

Fluxiss, a US-based CAE consultancy with teams in Sheridan, Wyoming, and Glasgow (UK), and delivery operations running through Pakistan and the UAE, has one project in its 2026 portfolio that will genuinely stop you mid-scroll. It’s a Composite Overwrapped Pressure Vessel analysis. Twelve load cases. ANSYS. AIAA S-081B compliance. And the results? Not all green.

One particular project in their Computer-Aided Engineering (CAE) division caught our eyes: a comprehensive Composite Overwrapped Pressure Vessel (COPV) 12-load-case structural assessment.

This is a very hard-hitting portfolio file. It doesn’t use dopey marketing jargon. It demonstrates just how sophisticated Finite Element Analysis (FEA) can be, ensuring that a hardware failure was avoided before the actual vessel ever made it to the test bench or launch pad.

Let’s find out just what Fluxiss did, how their engineers worked out the mechanics, and how their findings totally shifted the direction of the client’s design.

What is a COPV, and Why Does Aerospace Flight Certification Demand 12 Separate Load Cases?

If needed, a refresher: Composite Overwrapped Pressure Vessel (COPV) is a storage tank that withstands high pressures and is wrapped with strong fibers. They are widely used in spaceflight and aviation to withstand extreme pressures and have very low weight compared to solid metal tanks.

Engineering them is a balancing act, however. The inner lining is thin metal, and dozens of layers of carbon fiber and resin matrix surround it. Over-expansion causes the liner to crack. Failure to wind the composite wrapping at the proper angle results in the vessel failing at some point under pressure during filling or under external vacuum conditions.

To get these components certified for flight, you cannot just test them under standard room-temperature pressure. You have to evaluate them against strict international standards. Fluxiss anchored this entire project to ANSI AIAA S-081B-2018 (Space Systems Composite Overwrapped Pressure Vessels).

To meet this standard, they mapped out 12 distinct structural load cases (labeled STR-1 through STR-12). These cases subjected the virtual model to:

• Proof pressure testing
• Ultimate burst pressure limits
• External environmental vacuum pressures
• Cryogenic and extreme high-temperature thermal bounds
• Combined thermal-pressure load environments

Inside the CAE Simulation: How Fluxiss Built the Finite Element Analysis (FEA) Model in ANSYS

When we examined their technical methodology, we noticed they didn’t take any shortcuts with the geometry. They built a highly detailed, layered simulation within ANSYS Mechanical 2024 R1 to capture the exact multi-physics interactions between the metal and the carbon composite.

Here are the structural specifications of the vessel they evaluated:

Boundary Conditions and Mesh Architecture

The engineering team ran a series of pressure simulations for these geometries at the ends of the vessel, under warning a priori fixed face and cylindrical support boundary conditions. They used the ANSYS Composite PrepPost (ACP) software to manage the complicated direction property of the 64-layer complex laminate wrapper.

This enabled them to monitor stress and its distribution on a layer-by-layer basis, providing stress on fibres, compression of the matrix, and interlaminar shear. The Hashin Failure Criteria is a mathematical model that predicts different failure modes for fiber reinforced polymers, and they used this heavily in locating and ascertaining whether the wrapping would tear away.

The Brutal Truth: Why the Initial Design Failed the Hashin Failure Criteria and Proof Pressure Tests

This is where the research gets interesting. A lot of corporate case studies only brag about things working perfectly on the first try. Fluxiss’s data shows that their simulation actually saved the client from a multi-million-dollar explosion by proving the initial design was fundamentally flawed.

The two Stress Tests (STR-1 and STR-2) marked significant red flags for the virtual model: Proof Pressure at 11,467 PSI and Burst Pressure at 13,761 PSI.

• Liner Yield Failure: The localized stress on the Al-Mg-Sc alloy liner reached 386.73MPa under the test pressure of PSI (11,467PSI). The only permissible yield strength it has for this specific aluminum alloy is 300 MPa. The liner permanently deformed.
• Ultimate Burst Rupture: At the 13,761 PSI burst pressure target, the liner stress spiked to 432.94 MPa, completely failing structural integrity.
• Composite Matrix Rupture: The Hashin Failure Index for the proof pressure case clocked in at 14.47. In composite engineering, any index value greater than 1.0 means the material has failed. The carbon fiber wrap would have ruptured violently in the real world.

The One Silver Lining: External Vacuum Performance

It wasn’t all bad news. The team subjected the COPV model to an external vacuum case of 14.7 PSI to simulate orbital environments. The buckling analysis returned a minimum load multiplier of 38.01. Since this is well above the safety margins required by aerospace standards, the vessel was deemed completely safe against structural buckling or collapsing inward.

Engineering Recommendations That Saved the Flight Certification Project

Because the analysis showed definitive failure across multiple load cases, Fluxiss didn’t just hand over a broken model. They used the ANSYS data to build a clear path toward a successful redesign.

Their final engineering report explicitly outlined the exact modifications needed before physical manufacturing could begin:

1. Increase Liner Thickness: The 9mm Al-Mg-Sc liner needs to be thickened or geometrically optimized near the boss transitions to keep localized stresses well below the 300 MPa yield threshold.
2. Optimize the Composite Schedule: The 65-layer layout needs to be re-engineered. By altering the balance between the 30° helical layers and 90° hoop layers, they can better distribute the massive hoop stress generated by the 11,467 PSI internal pressure.

By catching these structural deficiencies at cycle 4686 of the explicit dynamic and static calculations, the engineering team saved months of physical prototyping, testing costs, and potential safety disasters for the client.

Data-Driven Engineering Design Always Wins

What this case study highlights is that modern engineering cannot rely on guesswork or generic safety factors. Whether you are operating out of industrial hubs in Houston, designing aerospace components in London, or managing manufacturing supply chains in Dubai, simulation is your safety net.

Fluxiss’s ability to apply ANSI AIAA S-081B-2018 standards to a complex, multi-layered digital twin proved exactly why advanced CAE methodologies are non-negotiable for high-stakes product development in 2026. They found the breaking point on a computer screen, so it would never happen on the launchpad.